Warmer winters and unseasonably hot spring days, together with increasingly unpredictable summer rainfall, are imperiling the iconic Rio Grande.
Never one for moderation, the Rio Grande has long been a “classic ‘feast or famine’ river, with a dry year or two typically followed by a couple of wet years that allow for recovery.” But a destabilizing climate is undermining the river’s historical resilience, reports the New York Times.
“The effect of long-term warming is to make it harder to count on snowmelt runoff in wet times,” David S. Gutzler, a climate scientist at the University of New Mexico, told the Times. “And it makes the dry times much harder than they used to be.”
Even in wet years, warmer winters mean precipitation increasingly falls as rain and drains swiftly away, rather accumulating as snow pack. “Spring temperatures have an impact, too, with warmer air causing more snow to turn to vapour and essentially disappear,” Gutzler explained.
And then there is the ever-present problem of the unpredictable summer “monsoon”—local parlance for summer thunderstorms.
This year, a great deal is riding on the soaking these storms will bring—should they arrive. “With spring runoff about one-sixth of average and more than 90% of New Mexico in severe to exceptional drought, conditions here are extreme,” reports the Times.
Charged with managing the river water that is regularly diverted to 62,000 acres of farmland along the shrinking river, hydrologist David Gensler of the Middle Rio Grande Conservancy District acknowledged that “if we use it up early in the season and don’t get any rain further on, the whole thing’s going to crash.” The odds of that outcome are further increased by an extended growing season that finds more plants taking up yet more water, “further reducing stream flows,” the Times notes.
Farmer Mario Rosales, who grows chilies and other crops on 365 acres along the river, knows the resource is in bad shape this year. His farm still thrives thanks to diverted water, and if the summer monsoons arrive, he will have a crop to roast and sell in the fall. “We’ve got a lot of faith,” he told Times reporter Henry Fountain. “We’ve always worked on faith.”
But state legislator Derrick J. Lente, whose Pueblo ancestors have been raising cattle in the area for generations, “recognizes that there is long-term trouble ahead,” writes Fountain. Elders describe the condition of the river as “the worst they’ve seen it in their lives,” Lente told him.
But preparing for an even drier Rio Grande is hard work, and even harder psychological labour. While he has made changes that help conserve water, Lente told the Times that he doesn’t “want to think” of a time without any water at all. “I really don’t,” he said. “We’d have to make some hard decisions.”